权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Mechanism of Energy Transduction and Substrate Activation in Biological Nitrogen Fixation

生物固氮中的能量转换和底物激活机制

基本信息

批准号：
10566582
负责人：
Faik Akif Tezcan
金额：
$ 28.32万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-01-15 至 2026-11-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10566582
关键词：
ATP Hydrolysis Active Sites Agriculture Ammonia Atmosphere Binding Binding Sites Biochemical Biological Biological Availability Biological Models Biological Products Biophysics Catalysis Cell physiology Chemicals Complex Couples Cryoelectron Microscopy Dependence Development Electron Transport Electrons Enzymes Goals Guanosine Triphosphate Health Human Investigation Location Maps Mechanics Mediating Metabolism Metals Methodology Molecular Conformation Molybdoferredoxin Mutagenesis Nature Nitrogen Fixation Nitrogenase Nucleotides Nutritional Oxidation-Reduction Persons Population Process Productivity Protein Dynamics Proteins Protons Reaction Research Research Project Grants Resolution Roentgen Rays Structure Substrate Interaction Testing Work enzyme model experimental study inhibitor innovation insight metalloenzyme particle programs small molecule spectroscopic survey stoichiometry welfare

项目摘要

PROJECT SUMMARY/ABSTRACT This proposal aims to elucidate how the bacterial metalloenzyme nitrogenase catalyzes the chemically difficult transformation of atmospheric dinitrogen into a bioavailable form, ammonia, and why/how it utilizes ATP hydrolysis to drive this reaction. Being the only enzyme responsible for reductive nitrogen fixation, nitrogenase sustains the agricultural/nutritional needs of ~40% of the human population. Aside from its global importance, nitrogenase is a unique model system with broad relevance to biological redox catalysis as well as ATP/GTP-dependent energy transduction processes, which are both central to proper cellular functioning and thus directly relevant to human health. Despite nearly five decades of extensive biochemical, biophysical, and structural characterization, the two most important questions about nitrogenase mechanism have not been answered in detail: a) Why and how ATP hydrolysis is ultimately utilized for the reduction of N2 or alternative substrates? b) What is the intimate mechanism of dinitrogen reduction on the nitrogenase active site metal cluster, FeMoco? The major experimental challenge in the investigations of nitrogenase arises from the fact that the catalytic activity of nitrogenase depends on continuous ATP turnover, which leads to a heterogeneous mixture of redox and nucleotide-bound states of nitrogenase that are difficult to distinguish from one another. To circumvent this challenge, we have initiated a research program in single-particle cryogenic electron microscopy (cryoEM) to structurally characterize dynamic states of nitrogenase at atomic resolution under enzymatic turnover conditions. Preliminary experiments have not only established the feasibility of this approach but also revealed unexpected structural features of nitrogenase which have fueled new mechanistic hypotheses. In the proposed project, we aim to build upon on these preliminary findings by a) mapping the ATP-driven conformational landscape of nitrogenase in unprecedented detail under catalytic turnover conditions and b) elucidating FeMoco structural dynamics and FeMoco-small molecule interactions in atomic resolution, while also c) contributing to the development of cutting-edge cryoEM methodologies for the structural interrogation of highly complex/dynamic protein assemblies and metallocofactors.

项目总结/文摘